scholarly journals Monitoring Land Surface Displacement over Xuzhou (China) in 2015–2018 through PCA-Based Correction Applied to SAR Interferometry

2019 ◽  
Vol 11 (12) ◽  
pp. 1494 ◽  
Author(s):  
Chen ◽  
Tan ◽  
Yan ◽  
Zhang ◽  
Zhang ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Land Surface ◽  
Urban Areas ◽  
Surface Deformation ◽  
Surface Displacement ◽  
Underground Water ◽  
Deformation Monitoring ◽  
Water Levels ◽  
Rapid Urbanization ◽  
Geological Conditions

Land surface deformation in metropolitan areas, which can cause varying degrees of hazard to both human lives and to properties, has been documented for decades in cities worldwide. Xuzhou, is one of the most important energy and industrial bases in eastern China, and has experienced significant land subsidence due to both excessive extraction of karst underground water and exploitation of mineral resources in recent decades. Furthermore, Xuzhou has recently undergone rapid urbanization in terms of urban expansion and underground construction, which could induce additional pressure on the urban land surface. However, most previous research on land surface deformation in the Xuzhou urban areas has been conducted based on traditional ground-based deformation monitoring techniques with sparse measurements. Little is known about the regional spatiotemporal behavior of land surface displacement in Xuzhou. In this study, a detailed interferometric synthetic aperture radar (InSAR) time series analysis was performed to characterize the spatial pattern and temporal evolution of land surface deformation in central areas of Xuzhou during 2015–2018. A method based on principal component analysis was adopted to correct artifacts in the InSAR signal. Results showed the correction strategy markedly reduced the discrepancy between global navigation satellite systems and InSAR measurements. Noticeable land subsidence (−5 to −41 mm/yr) was revealed widely within the Xuzhou urban areas, particularly along subway lines under construction, newly developed districts, and in old coal goafs. Remarkable consistent land uplift (up to +25 mm/yr) was found to have significantly affected two long narrow areas within the old goafs since 2015. The possible principal influencing factors contributing to the land surface displacements such as subway tunneling, building construction, mining, underground water levels and geological conditions are then discussed.

Land Subsidence in Delhi, India investigated using Sentinel-1 InSAR measurements

2020 ◽  
Author(s):  
Shagun Garg ◽  
Mahdi Motagh ◽  
Indu Jayaluxmi
Keyword(s):  
Land Subsidence ◽  
Land Surface ◽  
Surface Deformation ◽  
Field Measurements ◽  
Groundwater Depletion ◽  
National Capital Region ◽  
Rapid Urbanization ◽  
In Situ Data ◽  
Persistent Scatterers ◽  
The Government

<p>Groundwater induced land subsidence is a growing problem worldwide and has been documented in places like Mexico, Jakarta, Tehran, and China. India is the largest user of groundwater and pumps more than the USA and China combined. The National capital region(NCR) of India, due to rapid urbanization and illegal extraction, is facing severe groundwater depletion of the order of 0.5m-2m per year and is declared as a critical zone by the government of India. The looming crisis of groundwater depletion and supporting hydrogeology makes this region prone to land surface deformation.</p><p>Monitoring subsidence by conventional methods such as extensometers, leveling, hydrogeology modeling, and GPS requires precise field measurements and are time-consuming. With the advent of Interferometry, monitoring deformation precisely from the microwave sensors onboard satellite is possible. In our study, we demonstrate the result of the Persistent Scatterer InSAR (PS-InSAR) technique to monitor the subsidence in the Delhi NCR region using Sentinel -1 Interferometric wide swath (IW) mode. Descending pass datasets are used to identify the PSs over the study area. Fifty-six differential interferograms from Aug 2016 to Sep 2018 are formed after removing flat earth and topographic phase using SRTM 30m DEM. The PS-InSAR processing is done using Stanford Method for Persistent Scatterers (StaMPS), where an amplitude threshold index of 0.4 is selected for Initial PS candidate. The PS points are the stable targets which do not decorrelate much over time.  The deformation is calculated for all these PS points and a time series, and hence a velocity map is formed.</p><p>The rate of deformation in Southwest Delhi is found to be approximately 15 cm/year (max) in the radar line of sight direction. The in-situ data provided by the Central groundwater board (CGWB) India is not consistent and has many gaps. However, after applying Spatio-temporal interpolation, it follows the decreasing trend of Land subsidence which suggests that the groundwater extraction is the major cause for the subsidence in the southwest region of NCR during the observed period i.e., from 2016 -2018.</p>

scholarly journals Recent land subsidence caused by the rapid urban development in the Hanoi region (Vietnam) using ALOS InSAR data

2014 ◽  
Vol 14 (3) ◽  
pp. 657-674 ◽  
Author(s):  
V. K. Dang ◽  
C. Doubre ◽  
C. Weber ◽  
N. Gourmelen ◽  
F. Masson
Keyword(s):  
Spatial Distribution ◽  
Urban Development ◽  
Land Subsidence ◽  
Urban Areas ◽  
Surface Deformation ◽  
Seasonal Fluctuation ◽  
Urban Region ◽  
Rapid Urbanization ◽  
Groundwater Levels ◽  
Multi Temporal

Abstract. Since the 1990s the land subsidence due to the rapid urbanization has been considered a severely destructive hazard in the center of Hanoi City. Although previous studies and measurements have quantified the subsiding deformation in Hanoi center, no data exist for the newly established districts in the south and the west, where construction development has been most significant and where groundwater pumping has been very intensive over the last decade. With a multi-temporal InSAR approach, we quantify the spatial distribution of the land subsidence in the entire Hanoi urban region using ALOS images over the 2007–2011 period. The map of the mean subsidence velocity reveals that the northern bank of the Red River appears stable, whereas some areas in southern bank are subsiding with a mean vertical rate up to 68.0 mm yr−1, especially within the three new urban districts of Hoang Mai, Ha Dong – Thanh Xuan and Hoai Duc – Tu Liem. We interpret the spatial distribution of the surface deformation as the combination of the nature of the unsaturated layer, the lowering of groundwater in the aquifers due to pumping withdrawal capacity, the increase of built-up surfaces and the type of building foundation. The piezometric level in Qp aquifer lowers particularly after 2008, whereas the groundwater level in Qh aquifer remains steady, even if it loses its seasonal fluctuation in urban areas and drawdowns in neighboring water production plants. The time evolution deduced from the InSAR time series is consistent with previous leveling data and shows that the lowering rate of the surface slightly decreases till 2008. The analysis of groundwater levels in instrumented wells shows a correlation between the behavior of groundwater with the urban development and the acceleration of groundwater withdrawal. Also, the time variations suggest that the deformation became non-stationary, with upward and downward transient displacements related to the charge and discharge of the aquifers.

scholarly journals Surface Deformation Monitoring Using Time-lapse Microgravity Method in Central and East Lombok Regencies

2020 ◽  
Vol 31 (2) ◽  
pp. 16-23
Author(s):  
Suhayat Minardi ◽  
Teguh Ardianto ◽  
Alfina Taurida Alaydrus
Keyword(s):  
Land Subsidence ◽  
Land Surface ◽  
Surface Deformation ◽  
Time Lapse ◽  
Deformation Monitoring ◽  
Tectonic Activity ◽  
Gravity Measurement ◽  
Time Interval ◽  
Natural Occurrence ◽  
Gravitational Acceleration

Surface deformation is a natural occurrence on the surface of the earth. The deformation can be in the form of subsidence or uplifting of the land surface. In this research, an time-lapse microgravity method will be applied to monitor surface deformation that occurs in Central Lombok and East Lombok Districts. The method of time-lapse microgravity is repetitive gravity measurement at the same point with a certain time interval, the measured magnitude is a change in the value of the acceleration of gravity and the microGal scale. Measurements were made in August 2016, April 2018, and June 2019. The measured value of the change in gravitational acceleration is the superposition of the changes caused by subsurface and surface sources. Separation of the two values is carried out using striping filter, which takes into account the ratio of density, thickness, and depth of the surface and subsurface layers. Land subsidence occurred during the period August 2016 to April 2018 and land uplifting occurred during the April 2018 to June 2019 period. This land subsidence occurred due to natural compacting and minor tectonic activity (small earthquakes that were not felt) while land uplifting was occurred due to major tectonic activities, in the form of the Lombok Earthquake in July to September 2018.

scholarly journals Spatial-Temporal Evolution of Land Subsidence and Rebound over Xi’an in Western China Revealed by SBAS-InSAR Analysis

2020 ◽  
Vol 12 (22) ◽  
pp. 3756
Author(s):  
Wei Shi ◽  
Guan Chen ◽  
Xingmin Meng ◽  
Wanyu Jiang ◽  
Yan Chong ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Groundwater Level ◽  
Surface Deformation ◽  
Western China ◽  
Ground Subsidence ◽  
Underground Space ◽  
Large Area ◽  
Space Utilization ◽  
Rapid Urbanization ◽  
Ground Fissures

Land subsidence is one of the major urban geological hazards, which seriously restricts the development of many cities in the world. As one of the major cities in China, Xi’an has also been experiencing a large area of land subsidence due to excessive exploitation of groundwater. Since the Heihe Water Transfer Project (HWTP) became fully operational in late 2003, the problem of subsidence has been restrained, but other issues, such as ground rebounds, have appeared, and the effect of the underground space utilization on land subsidence remains unsolved. The spatial-temporal pattern of land subsidence and rebound in Xi’an after HWTP and their possible cause have so far not been well understood. In this study, the evolutionary characteristics of land subsidence and rebound in Xi’an city from 2007–2019 was investigated using Small Baseline Subset Interferometric Synthetic Aperture Radar (SBAS-SAR) technology to process the Advanced Land Observing Satellite (ALOS) and Sentinel-1A SAR datasets, and their cause and the correlation with groundwater level changes and the underground space utilization were discussed. We found that the land subsidence rate in the study area slowed from 2007–2019, and the subsidence area shrank and gradually developed into three relatively independent and isolated subsidence areas primarily. Significant local rebound deformation up to 22 mm/y commenced in the groundwater recharge region during 2015–2019. The magnitude of local rebound was dominated by the rise in groundwater level due to HWTP, whereas tectonic faults and ground fissures control the range of subsidence and the uplift area. The influence of building load on surface deformation became increasingly evident and primarily manifested by slowing the subsidence reduction trend. Additionally, land subsidence caused by the disturbances during the subway construction period was stronger than that in the operational stage. Future land subsidence in Xi’an is predicted to be alleviated overall, and the areas of rebound deformation will continue increasing for a limited time. However, uneven settlement range may extend to the Qujiang and Xixian New District due to the rapid urban construction. Our results could provide a scientific basis for land subsidence hazard mitigation, underground space planning, and groundwater management in Xi’an or similar regions where severe ground subsidence was induced by rapid urbanization.

scholarly journals Copernicus Sentinel-1 MT-InSAR, GNSS and Seismic Monitoring of Deformation Patterns and Trends at the Methana Volcano, Greece

2020 ◽  
Vol 10 (18) ◽  
pp. 6445 ◽  
Author(s):  
Theodoros Gatsios ◽  
Francesca Cigna ◽  
Deodato Tapete ◽  
Vassilis Sakkas ◽  
Kyriaki Pavlou ◽  
...  
Keyword(s):  
Land Surface ◽  
Surface Deformation ◽  
Ground Deformation ◽  
Local Population ◽  
Seasonal Fluctuation ◽  
Satellite System ◽  
Deformation Monitoring ◽  
Persistent Scatterers ◽  
Geothermal Activity ◽  
Global Navigation Satellite

The Methana volcano in Greece belongs to the western part of the Hellenic Volcanic Arc, where the African and Eurasian tectonic plates converge at a rate of approximately 3 cm/year. While volcanic hazard in Methana is considered low, the neotectonic basin constituting the Saronic Gulf area is seismically active and there is evidence of local geothermal activity. Monitoring is therefore crucial to characterize any activity at the volcano that could impact the local population. This study aims to detect surface deformation in the whole Methana peninsula based on a long stack of 99 Sentinel-1 C-band Synthetic Aperture Radar (SAR) images in interferometric wide swath mode acquired in March 2015–August 2019. A Multi-Temporal Interferometric SAR (MT-InSAR) processing approach is exploited using the Interferometric Point Target Analysis (IPTA) method, involving the extraction of a network of targets including both Persistent Scatterers (PS) and Distributed Scatterers (DS) to augment the monitoring capability across the varied land cover of the peninsula. Satellite geodetic data from 2006–2019 Global Positioning System (GPS) benchmark surveying are used to calibrate and validate the MT-InSAR results. Deformation monitoring records from permanent Global Navigation Satellite System (GNSS) stations, two of which were installed within the peninsula in 2004 (METH) and 2019 (MTNA), are also exploited for interpretation of the regional deformation scenario. Geological, topographic, and 2006–2019 seismological data enable better understanding of the ground deformation observed. Line-of-sight displacement velocities of the over 4700 PS and 6200 DS within the peninsula are from −18.1 to +7.5 mm/year. The MT-InSAR data suggest a complex displacement pattern across the volcano edifice, including local-scale land surface processes. In Methana town, ground stability is found on volcanoclasts and limestone for the majority of the urban area footprint while some deformation is observed in the suburban zones. At the Mavri Petra andesitic dome, time series of the exceptionally dense PS/DS network across blocks of agglomerate and cinder reveal seasonal fluctuation (5 mm amplitude) overlapping the long-term stable trend. Given the steepness of the slopes along the eastern flank of the volcano, displacement patterns may indicate mass movements. The GNSS, seismological and MT-InSAR analyses lead to a first account of deformation processes and their temporal evolution over the last years for Methana, thus providing initial information to feed into the volcano baseline hazard assessment and monitoring system.

scholarly journals LAND SUBSIDENCE MONITORING USING PS-InSAR TECHNIQUE FOR L-BAND SAR DATA

2016 ◽  
Vol XLI-B7 ◽  
pp. 995-997 ◽  
Author(s):  
S. Thapa ◽  
R. S. Chatterjee ◽  
K. B. Singh ◽  
D. Kumar
Keyword(s):  
Time Series ◽  
Land Subsidence ◽  
Land Surface ◽  
Surface Deformation ◽  
Underground Mining ◽  
Ground Surface ◽  
Sar Interferometry ◽  
Persistent Scatterer Interferometry ◽  
Long Time ◽  
Subsidence Monitoring

Differential SAR-Interferometry (D-InSAR) is one of the potential source to measure land surface motion induced due to underground coal mining. However, this technique has many limitation such as atmospheric in homogeneities, spatial de-correlation, and temporal decorrelation. Persistent Scatterer Interferometry synthetic aperture radar (PS-InSAR) belongs to a family of time series InSAR technique, which utilizes the properties of some of the stable natural and anthropogenic targets which remain coherent over long time period. In this study PS-InSAR technique has been used to monitor land subsidence over selected location of Jharia Coal field which has been correlated with the ground levelling measurement. This time series deformation observed using PS InSAR helped us to understand the nature of the ground surface deformation due to underground mining activity.

scholarly journals Analysis of land subsidence changes on the Beijing Plain from 2004 to 2015

2020 ◽  
Vol 382 ◽  
pp. 291-296
Author(s):  
Lin Guo ◽  
Huili Gong ◽  
Xiaojuan Li ◽  
Lin Zhu ◽  
Wei Lv ◽  
...  
Keyword(s):  
Land Subsidence ◽  
Surface Deformation ◽  
Kendall Test ◽  
Alluvial Fan ◽  
Water Diversion ◽  
Grid Cells ◽  
Plain Area ◽  
Beijing Plain ◽  
Grid Unit ◽  
Geological Conditions

Abstract. Land subsidence, as a surface response to the development, utilization and evolution of underground space, has become a global and multidisciplinary complex geological environment problem. Since the 1960s, land subsidence has been developing rapidly in the Beijing Plain area. Against the backdrop of the integration of Beijing, Tianjin and Hebei in addition to “southern water” (South-to-North Water Diversion Project, SNWDP) entering Beijing, the systematic study of the evolution mechanism of land subsidence is of great significance for the sustainable development of the regional economy. Firstly, this study used ENVISAT ASAR and RADARSAT-2 data to obtain surface deformation information for the Beijing Plain area from 2004 to 2015 and then verified the results. Secondly, the study area was divided into units using a 960 m×960 m grid, and the ground settlement rate of each grid unit from 2004 to 2015 was obtained. Finally, the Mann–Kendall test was performed on the grid to obtain the mutation information for each grid unit. Combined with hydrogeology and basic geological conditions, we have attempted to analyze the causes of the mutations in the grid. The results show that 2347 grid cells were mutated in a single year, with most of these distributed across the Yongding River alluvial fan and the middle and lower parts of the Chaobai River alluvial fan. A total of 1128 grid cells were mutated in multiple years, with the majority of these cells mainly distributed across the upper-middle area of the alluvial fan, near the emergency water source and at the edge of the groundwater funnel. This study aims to provide favorable technical support and a scientific basis for urban construction in Beijing.

scholarly journals Effects of Urbanization on Storm Water Run-off : A Case Study of Kathmandu Metropolitan City, Nepal

2016 ◽  
Vol 11 (1) ◽  
pp. 36-49 ◽  
Author(s):  
Ashim Ratna Bajracharya ◽  
Ritu Raj Rai ◽  
Shreema Rana
Keyword(s):  
Land Surface ◽  
Urban Areas ◽  
Hydrological Cycle ◽  
Water Cycle ◽  
Surface Characteristics ◽  
Impervious Surfaces ◽  
Rapid Urbanization ◽  
Metropolitan City ◽  
Run Off ◽  
The City

In urban and suburban areas, much of the land surface is covered by buildings and pavements, which do not allow precipitation and snowmelt to soak into the ground. Instead, most developed areas rely on storm drains to carry large amounts of runoff from roofs and paved areas to nearby waterways. Hard surfaces such as streets, parking lots and built-up areas are impervious surfaces through which, water cannot pass through. As more and more landscapes are covered with hard impervious surfaces, the amount of water that infltrates, decreases and the amount that runs off, increases. This research is focused on studying run-off conditions in context of urban areas. The study area is Kathmandu Metropolitan City (KMC). The City is in the stage of rapid urbanization and with it, a rapid increase in built-up spaces. As a result, the city is losing a balance between impervious and pervious cover. Loss of greeneries and unpaved open spaces are causing rapid drain of rain-water. This is creating a disturbance in the hydrological cycle of the area. For assessing the extent of runoff, total runoff was estimated of KMC, as per the surface characteristics and using rational method for calculation.  Parameters for determining run-off coeffcients were mainly land cover and land use data, soil type and slope of surface. Results show that current runoff is alarmingly high, indicated by the difference between the run-off values of pre and post-development scenarios. Urban development pattern has caused a major impact, in the prevailing run-off and it is very crucial that these issues are addressed in urban planning to promote effective solutions for maintaining water cycle and water resources in urban areas. Journal of the Institute of Engineering, 2015, 11(1): 36-49 

scholarly journals Evaluation of Urban Heat Island (UHI) Using Satellite Images in Densely Populated Cities of South Asia

Earth ◽  
2021 ◽  
Vol 2 (1) ◽  
pp. 86-110
Author(s):  
Manisha Maharjan ◽  
Anil Aryal ◽  
Bijay Man Shakya ◽  
Rocky Talchabhadel ◽  
Bhesh Raj Thapa ◽  
...  
Keyword(s):  
Surface Temperature ◽  
Urban Heat Island ◽  
South Asia ◽  
Land Surface ◽  
Urban Areas ◽  
Well Being ◽  
Heat Island ◽  
Rapid Urbanization ◽  
Urban Heat ◽  
The Impact

Rapid Urbanization, and other anthropogenic activities, have amplified the change in land-use transition from green space to heat emission in built-up areas globally. As a result, there has been an increase in the land surface temperature (LST) causing the Urban Heat Island (UHI) effect, particularly in large cities. The UHI effect poses a serious risk to human health and well-being, magnified in large developing cities with limited resources to cope with such issues. This study focuses on understanding the UHI effect in Kathmandu Valley (KV), Delhi, and Dhaka, three growing cities in South Asia. The UHI effect was evaluated by analyzing the UHI intensity of the city with respect to the surroundings. We found that the central urban area, of all three cities, experienced more heat zones compared to the peri-urban areas. The estimated average surface temperature ranged from 21.1 ∘C in March 2014 to 32.0 ∘C in June 2015 in KV, while Delhi and Dhaka experienced surface temperature variation from 29.7 ∘C in June 2017 to 40.2 ∘C in June 2019 and 23.6 ∘C in March 2017 to 33.2 ∘C in March 2014, respectively. Based on magnitude and variation of LST, highly built-up central KV showed heat island characteristics. In both Delhi and Dhaka, the western regions showed the UHI effect. Overall, this study finds that the UHI zones are more concentrated near the urban business centers with high population density. The results suggest that most areas in these cities have a rising LST trend and are on the verge of being UHI regions. Therefore, it is essential that further detailed assessment is conducted to understand and abate the impact of the temperature variations.

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